- Joined
- May 16, 2001
- Location
- Denver, CO
There has been several debates over the maxium amount of memory Win9x can handle. I hope this explains it. Remember that this is just an informed opinion.
The Windows 32-bit protected-mode cache driver (Vcache) determines the maximum cache size based on the amount of RAM that is present when Windows starts. Vcache then reserves enough memory addresses to permit it to access a cache of the maximum size so that it can increase the cache to that size if needed. These addresses are allocated in a range of virtual addresses from 0xC0000000 through 0xFFFFFFFF (3 to 4 gigabytes) known as the system arena.
On computers with large amounts of RAM, the maximum cache size can be large enough that Vcache consumes all of the addresses in the system arena, leaving no virtual memory addresses available for other functions such as opening an MS-DOS prompt (creating a new virtual machine).
This problem may occur more readily with Advanced Graphics Port (AGP) video adapters because the AGP aperture is also mapped to addresses in the system arena. For example, if Vcache is using a maximum cache size of 800MB and an AGP video adapter has a 128MB aperture mapped, there is very little address space remaining for the other system code and data that must occupy this range of virtual addresses.
And here are the three suggested workarounds:
1. Physically remove any memory in excess of 512MB [!]
2. Use the System Configuration utility to limit the amount of memory that Windows uses to 512MB or less.
3. Use the MaxFileCache setting in the System.ini file to reduce the maximum amount of memory that Vcache uses to 512MB (524,288 KB) or less.
Back when I had Win9x I kept it to 256mb and all my benchmarks were higher than using 384 or 512.
The Windows 32-bit protected-mode cache driver (Vcache) determines the maximum cache size based on the amount of RAM that is present when Windows starts. Vcache then reserves enough memory addresses to permit it to access a cache of the maximum size so that it can increase the cache to that size if needed. These addresses are allocated in a range of virtual addresses from 0xC0000000 through 0xFFFFFFFF (3 to 4 gigabytes) known as the system arena.
On computers with large amounts of RAM, the maximum cache size can be large enough that Vcache consumes all of the addresses in the system arena, leaving no virtual memory addresses available for other functions such as opening an MS-DOS prompt (creating a new virtual machine).
This problem may occur more readily with Advanced Graphics Port (AGP) video adapters because the AGP aperture is also mapped to addresses in the system arena. For example, if Vcache is using a maximum cache size of 800MB and an AGP video adapter has a 128MB aperture mapped, there is very little address space remaining for the other system code and data that must occupy this range of virtual addresses.
And here are the three suggested workarounds:
1. Physically remove any memory in excess of 512MB [!]
2. Use the System Configuration utility to limit the amount of memory that Windows uses to 512MB or less.
3. Use the MaxFileCache setting in the System.ini file to reduce the maximum amount of memory that Vcache uses to 512MB (524,288 KB) or less.
Back when I had Win9x I kept it to 256mb and all my benchmarks were higher than using 384 or 512.
